Multiple effect flash evaporator



Mn- W70 LE ROY A. BROMLEY ET AL 3,487,873

MULTIPLE EFFECT FLASH EVAPORTOR 4 Shets-Sheet l Filed F'eb. l5, 1967 AllNN .BDO LEQQDQQ mi Smilmk .D S my M W 2% N .NMEA m WOR. L f WMM@ m .YYEN. ww YLO ONH mmm LSA# VI B VN @Summum I S I Mllu mm3@ mEq Mw@ WN jan.6, R97@ LE ROY A. BROMLEY ET AL 3,487,873

MULTIPLE EFFECT FLASH EVAPORATOR 4 Sheets-Sheet 8 Filed Feb. l5,

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Jan. 6, R97@ LE ROY A. BROMLEY ET Al. 3,487,83

MULTIPLE EFFECT FLASH EVAPORATOR .Filed Feb. 15, 1967 4sheetS-sheet s20a /26 ,93 21a CONGE/V TRA TED aw BRI/VE /NER 7'5 TO V4 OUUM lm/ENTORSLEROY A. @Rom/5r 5mn/5r M. READ By A/v rHo/vr E. afg/wom) A T TOR/VE YS'hn. 6, W7@ LE ROY A. BROMLEY ET AL 3487,873

MULTIPLE EFFECT FLASH EVAPORATOR Filed Feb. l5, 1967 4 Sheets-Sheet 4.

CONDE NSA TE TO BO/ L El? co/vcE/VTRATED .comm/r .J 70 270 cooLA/vr mWASTE "88 :i2/L PRODUCT Fi 8 INVENTORS Q LeRoy A. @R0/MLU snm/LEY M.REA@ BY A/vrHo/w E. om Mo/vo ,L A TTOR/VEYS United States Patent O Im.C1. Bold 1/22 U.S. Cl. 159 l3 10 Claims ABSTRACT OF THE DISCLOSUREMethod of and apparatus for distilling liquid, which comprises apparatusfor conducting liquid from a container in which the liquid is beingheated to a second cOntainer through a plurality of tubes, the inlets ofthe tubes being restricted for causing a pressure drop and consequentvaporization of a portion of the liquid. The liquid entering the secondcontainer is conducted therefrom to a third container through its tubesand restrictors as aforementioned for causing a further pressure dropand vaporization. The vapor emanating from the tubes of the iirstmentioned container is subjected to the environment of the tubes in thesecond mentioned container whereby that vapor is condensed to adistillate.

ends of the tubes provide for most of` the pressure drop between the twocontainers. Separate conduits drain the distillate from the lowercontainer. The lowercontainer is also provided with tubes andrestrictors connected with the receiver and those tubes lead to a thirdcontainer. Pressure drop and vaporization occurs in the tubes. The vaporemanating from the tubes of the rst mentioned 'container are subjectedto the chilling effect of the tubes in the second mentioned chambercondense into a distillate.

The present invention is a continuation-in-part applicacausing the vaporto Vtion of our copending application, Ser. No. 348,550, led

Mar. 2, 1964 and now abandoned.

The prior art, such as the Hickman Patent No. 2,894,879, requires acomplicated mechanism for producing centrifugal force to propel liquidsacross the evap- `orating and condensing surfaces. The prior art, suchas the Holtslag Patent No. 3,175,962, provides downwardly increasingdiameter tubes between the upper and lower compartments, not fordeveloping a high velocity ow, but' for the contrary purpose ofmaintaining a film of 3,487,873 Patented Jan. 6, i970 ICC distillantthrough the lengths of the tubes to overcome the detrimental factor ofthe constant diameter tubes in such systems as is disclosed in theLustenader et al. Patent No. 3,099,607.

Suitable means is provided for withdrawing inert gases from thecontainers, and means is provided for further cooling the distillateafter it is subjected to the last stage of distilling.

In one embodiment, each of the conduits for draining distillate from thefloors of the containers is in intimate heat exchange relationship withthe depending tubes, and, in that embodiment, those conduits extendthrough depending tubes.

In a second embodiment, at least some of the receivers include wellswhich extend below the upper or receiving ends of the respective tubesconnected with the receiver; the receiver also includes a basin forreceiving the liquor from the tubes of receivers thereabove; a tube isconnected with the basin for delivering liquor to the Well. The conduitsfor conducting distillates from containers are in heat exchangerelationship with the liquid below the floors of the containers fromwhich the conduits receive the distillate.

In a third embodiment, the distillate: is drained from upper containersto lower containers through conduits in the floors of the uppercontainers.

Also, in each of the embodiments, the lower portion of the evaporator isprovided with an inlet manifold which is connected with the uppermanifold by `a series of tubes, and these tubes are subjected to heatwithin the compartments aforementioned.

Also, the inside diameter of at least some of the lower tubes, leadingfrom the receivers, are larger than some of the tubes thereabove.

Other features and the advantages of the present invention will beapparent from the following description, reference being had to theaccompanying drawings wherein preferred embodiments of the invention areillustrated.

In the drawings:

FIG. 1 is a diagrammatic view showing the present invention in a systemfor converting sea water to fresh water;

FIG. 2 is a longitudinal sectional view of the multiple effect ashevaporator, shown diagrammatically in een tain aspects, and some of thecompartments or stations for conversion have been omitted;

FIG. 3 is a fragmentary view in cross-section, the section being takenalong line 3 3 of FIG. 2, but on a larger scale;

FIG. 4 is a fragmentary view in section of part of the evaporator shownin FIG. 2, but on a larger scale;

FIG. 5 is a view similar to FIG. 2, but showing another aspect of theinvention;

FIG. 6 is a fragmentary sectional view taken along line 6 6 of FIG. 5,but on a larger scale;

FIG. 7 is a fragmentary sectional View taken along line 7 7 of FIG. 6;

FIG. 8 is a view similar to FIG. 5, but showing another aspect of theinvention; and

FIG. 9 is a fragmentary sectional view taken along line 9 9 of FIG. 8,but on a larger scale.

Referring first to FIG. 1, the system is shown at 20 and the evaporatoris shown at 22. Sea water is delivered to a compartment 24 by a pipe 26.This compartment contains bars and screens (not shown) for removingextraneous matter, such as weeds and other matter contained in thewater. Water then flows by pipe 2-8 to a tank 30 containing tine screensor filtration articles (not shown). Water then liows by pipe 32 throughan element 34, where acid is applied to the water, and then water flowsby pipe 36 to a water pump 38. Water emanating from the pump is carriedby a pipe 40, the end of which is open for the escape of CO2. The wateremanating from the end of the pipe 40 is caught by a funnel 42 anddelivered to a tank 44 containing de-aerator mechanisms (not shown). Thewater flows from tank 44 by a pipe 46 to a pump 48 and delivered to thelower end of the evaporator 22 by a pipe 50. After treatment in theevaporator, the product, namely fresh water, is withdrawn from theevaporator through a pipe 52 to a pum 54 and delivered from the pump bya pipe '56.

Brine is withdrawn from the lower portion of the evaporator by a pump 58through a pipe 60, and is connected from the pump K8 by a pipe 62.

A pipe 64 is connected to pipe 28 for delivering Water to a pump 66.This pump discharges into a pipe 68 connected with a cooling element 70,contained in the lower portion of the evaporator. This water functionsas a coolant within the evaporator. Water is conducted from the coolingelement 70 by a pipe 72 which is joined with pipe `62.

An extraneous source of heat is used to heat the upper part of theevaporator. This extraneous source includes a boiler 74 which isconnected to a heating element, shown diagrammatically as a coil 76.Steam is delivered to the heating element 76 by a pipe 78, and hot wateris returned to the boiler by a pipe `80.

Gases are withdrawn from the tank 44 and the evaporator 22 by anejector, shown diagrammatically at 82. This ejector is actuated by steamdelivered thereto from the boiler by a pipe 84. Gases are delivered tothe ejector 82 from the tank 44 by a pipe y86 and are delivered to theejector from the bottom of the evaporator by a pipe 88. These gases andsteam flow through an outlet pipe 90.

The system generally shown in FIG. 1 is more or less standard for seawater conversion.

Referring now to the evaporator 22 shown in detail in FIGS. 2 and 3, itincludes an elongated vertically extend ing tank or tower 92 whichencloses a manifold 94 in the extreme bottom thereof. This manifoldreceives liquid (sea water) from pipe 50. This lower manifold 94 isconnected by a series of tubes 96 to an upper manifold or top container`98, disposed in the top portion of the tower 92. The tower, in additionto manifold or container 98, includes a plurality of superimposedcontainers. While only four containers are shown fully, it is to beunderstood that an additional number of compartments are usuallydesired.

These four containers are shown, and parts of two other containers areshown at 101, 102, 103, 104, 105, 106 and 107. Manifold 9-8 is providedwith a floor 108;

containers 101, 102 and 103 are provided with iioors y Y and heats tubes122 and tubes 96 in container 101. Liquid from the manifold 98 flowsthrough tubes 122 and into container 102. A restrictor 126 is providedat the inlet to each of the tubes 122 in the form of an orifice ofapproximately one-tenth inch in diameter. In this manner, pressure drop,expansion and vaporization takes place in the tubes 122. The vapor inthe form of distilled steam in container 102, upon condensing, falls tothe floor 112 of that container, which iioor functions as a receiver forthe condensate.

The liquid emanating from tubes 122 in container 101 falls into areceiver 128 in container 102. This receiver includes an open top pan130, and a series of tubes 132, similar to tubes 122, which depend fromthe bottom of the pan. These tubes 132 extend through openings 124 inthe oor 112 of container 102. Expansion takes place in tubes 13-2, aspreviously explained With respect to tubes 122. The vapor emanating fromthe bottom of the tubes 132 in container 102, upon condensing, falls tothe floor 114 of container 103, while the liquor falling into container103 is received by a receiver 134 in container 103. This receiver issimilar to receiver 128 in that it includes a pan 136 and dependingtubes 138.

Similar receivers 140 and 142 are disposed in containers 105 and 106,respectively, and in all containers between containers 103 and 105` Thetubes for these receivers are shown at 144 and 146, respectively. Alldepending tubes of all receivers are provided with restrictors 126. Itis to be observed that the diameter of tubes 138 of container 103 may beslightly larger than the diameter of tubes 132 in container V102. Thesame variation in diameter is ypresent with respect to tubes 146 incontainer 106, and tubes 144 in container 105, while the diameters oftubes 144 and 146 are considerably larger than tubes 132 and 138.

Each of the containers form a stage in which expansion and condensationof distillate takes place, and, in a system employing, for example,fifteen stages (fifteen containers), the depending tubes of at leastsome of the receivers in certain lower containers are increased indiameter progressively downwardly. Those tubes in container 101 willhave an inside diameter of approximately one-half inch, and the tubes146 in container 106 will have an inside diameter of approximately oneand onehalf inches. This increase in diameter of depending tubes isdesirable because the specific volume of the vapor increases andthepressure drop between stages decreases.

Container 107 isalso provided with a receiver 147 in the form of a pan148 `for concentrated brine. 'Ihis receiver is connected with lthe brineoutlet pipe 60.

Each of the oors of the containers 102, 103, 104, and 106 is providedwith at least one drain tube 150, 152, |154, 156 and`158, respectively.Similar drain tubes are provided for each container, intermediatecontainers 104 and 105. These tubes have Ian inside diameter ofapproximately one-quarter inch, and each extends through fluid presentbelow the oor being drained thereby, and in the embodiment shown inFIGS. 2 and 3, the conduits extend through depending tubes therebelow ofeach receiver, having a depending tube. For example, tube 150 extends,as shown, through depending tubes 1138, 144 and 146, and also throughdepending tubes of each receiver which is interposed between receivers134 and 140. Thus, the drain tubes for the distillate are in intimateheat exchange relationship with the sea water in the depending tubes ofreceivers. These dnain tubes extend through holes 149 in the bottom ofreceiver 148 in container 107, and the distillate falls to the bottom ofthat container and is conveyed therefrom by pipe 52. The cooling element70 effects condensation of all vapor being generated in container 107.While only tive drain tubes arel shown, it is to be understood thatthere will be Iat least las many drain tubes as there are containers inwhich distillation takes place, for example, fifteen.

The number of containers or stations elected could depend on economicconsideration of the various factors encountered, such as the cost ofheating, equipment necessary, maintenance problems. For example, fifteensuperimposed containers may be desirable. In the embodiment, only fourcontainers are being fully shown together with the upper part of onecontainer and the lower part of another. Y

Dellectors 160 depend from the bottoms of the doors for guiding liquorto the pans of the receivers.

Referring now to the embodiment shown in FIGS. 5, 6 and 7, there theevaporator tank or tower is shown at 192. In this embodiment, the toweris in the form of a frustum of a cone. -Lke in FIGS.'2, 3 and 4, thetower encloses 1lower manifold 1194 which is connected by a series oftubes 196 with an lupper manifold 198.

Containers are shown at 201, 202, 203, 204, 205, 206

and 207, the fourteenth container being shown at 206 and the fifteenthat 207. Manifold 198 is provided with a door 208 and containers 201,202, 203, 204, 206 land 207 are provided, respectively, with doors 210,212, 214, 216, 218 and 220.

A series of tubes 222 depends from door 208 of manifold 198. These-tubes extend through openings 224 in t-he door 210 of container 201.The container 201 forms the major heating element, diagrammaticallyshown at 76 in FIG. l. It receives steam from pipe 78 land thecondensate is removed through pipe 30. The steam surrounds and heatstubes 222 and 196 in container 201. Liquid from manifold 198 ows throughtubes 222 into container 202. A restrictor, like 126 in FIGS. 2 and 3,is provided at the inlet of each tube 222. Expansion and vaporizationtakes pl-ace in the tubes 222.

The Ivapor, `upon condensing, falls to oor 212 of container 202. Liquidfalling from tubes 222 is directed by deflector 260 and enters areceiver 228 in the same manner as in FIG. 2. The receiver includes anopen top pan 230 and a series of tubes 232, similar to tubes 222,depends from the bottom of the pan. These tubes extend through openings224 in door 212 of container 202. The inlets of the tubes are providedwith restrictors 126. Expansion takes place in tubes 232, ias previouslyexplained with respect to tubes 222, `and vapor, upon condensing, fallsto the door 214 of container 203, and the liquid, falling from the tubes232, is caught in a receiver 234 in container 203.

Receiver 234 includes |a pan 236 having a centrally disposed well 231which extends to the floor 214. Receiver 234 also includes la catchbasin 233, the bottom of which is connected to la downwardly extendingtube 235 which extends into the lwell 231 and terminates near the bottomof the well. Liquid emanating yfrom the tubes 232 is directed bydellector 260 into the catch basin 233, flows downwardly through thetube 235 into the -well and then upwardly `into the pan 236 of thereceiver. A series of tubes, similar to tubes 222 and 232, depends frompan 236 and extends through opening 224 in the floor 214. The inlet endsof tubes 38 are provided with restrictors 126.

Similar receivers 240 and 242 `are disposed in containers 204 and 206,respectively, and in all containers interposed between containers 204and 206. The depending tubes for receivers 240 and 242 are shown at 244and 245, respectively. Each tube is provided with a restrictor 126 atthe inlet end thereof. It will be observed that tubes 232 may beslightly larger in inside diameter than tubes 222, 4and that `tubes 240may be considerably larger in diameter than tubes 245. In an evaporatorhaving, for example, fifteen stages I(fifteen superimposed stages) someof the expansion tubes in at least certain of the lower containers Iareincreased in diameter progressively dolwnwardly. Those tubes incontainer 201 will have lan inside diameter of approximately one-halfinch, and the tubes 245 in container 206 will have an inside diameter ofyapproximately one and one-half inches.

Container 207 is also provided with a receiver 247 including a pan 248.It is also provided with a well 23'1, a catch basin 233 and a dependingtube 235, for receiving liquid emanating from `tubes 245. Theconcentrated brine is drained from the pan 248 by pipe 60.

Each floor of containers 202 to 206 is provided with at least one draintube, each being shown as having two drain tubes 250, 252, 254, 256 and.258, respectively. The drain pipe 254 for the compartment 204 is notshown in compartment 6 in FIGS. 5 and 7, since it is apparent from FIG.6 that some pipes are behind others and cannot be seen. Similar draintubes are provided lfor the containers (not shown) which are disposedbetween containers 204 and 206. These drain tubes are in intimate heatexchange relative with the liquid for the duel purpose of cooling thedistillate and for heating the liquid. These ttubes are shown asextending through the wells of the receiver; they surround the tubeswhich extend down- Iwardly from the catch basins. The drain tubes extendthrough openings 249 in the bottom of pan 248. The distillate falls tothe floor 220 of container 207 and is drained from that container bypipe 52. The cooling element 70 effects condensation of all lvaporgenerated in container 207.

Since liquid, upon entering the basins, must irst pass downwardlythrough the tubes 235 and then upwardly through wells 231 beforeentering the receiver pan, and since the drain tubes surround the tubes235, desirable heat exchange relationship is provided between the liquidand the distillate.

Since it is desirable to progressively increase the diameters of theexpansion tubes, it is also desirable to maintain a large number ofthese expansion tubes, and since it is desirable to have the drain tubesfor the distillate in heat exchange relationship with the liquid in thewells of the receivers, the widths of the receiver pans, the wells tandthe basins have been increased.

Vapor surrounding these depending tubes gives up its heat to the liquidfalling through these tubes, resulting in condensation of vapor aboutthe tubes and the heat, being transferred to the liquid, assets inevaporation within the tubes.

Referring now to the embodiment shown in FIGS. 8 and 9, the drain tubes250, 252, 254, 256 and 258, and similar drain tubes for the containers(not shown), have been eliminated, and in their stead, a series ofconduits 262 is provided in each of the oors 212, 214, 216 and 218, andin the floors of the containers (not shown), for draining the distillateto the next below container. These conduits 262 are disposed radiallyoutwardly beyond the peripheries of the pans of the containers nextbelow the container being drained.

Inert gases are withdrawn from each of the containers 202, 203, 204,205, 206 and the containers (not shown) through tubes. The tubes forcontainers 202 to 206 are shown at 264, 265, 266, 267 and 268,respectively. The inlets for tubes 265 to 268 are in the shape offunnels 270 for receiving not only the inert gases from the gas tubesthereabove, but also from the container which it drains. The inert gastube 8S is also provided with a funnel-shaped inlet for receiving gasfrom container 206 and all gas owing downwardly from gas tube 267.

The elimination of tubes 259, 252, 254, 256, 258 and like tubes for thecontainers (not shown), materially simplies the construction related tothe embodiments shown in FIGS. 2 to 7 using such tubes.

The advantage of the present invention will ble readily apparent tothose skilled in the art from the table following, wherein comparisonsare made between the present multiple effect flash evaporator (referredto as MEF) and a typical multi-stage dash evaporator (referred to as F),and a typical multiple effect evaporator (referred to as E).

COMPARISON OF PROPOSED MULTIPLE EFFECT FLASH EVAPVORATOR SYSTEM (MEF)WITH A TYPICAL MULTI-STAGE FLASH EVAPORATOR (F), AND A TYPICAL MULTIPLEEFFECT EVAPORATOR (E) Fair or Comments (Refer to MEF system unlessotherwise Item poor Good Better Best stated) Number oi stages(thermodynamic efIiciency) F E MEF A smaller number of stages for thesame product to steam ratio is a measure of thermodynamic efficiency.

Volume of equipment F E MEF This a dcrude measure oi the capitalinvestment req e Arrangement is very similar to multi-stage ashSimplicity of ow scheme; system, Internal stage structure of MEF is moreInternal E MEF complex than F, but external arrangement in- External E FMEF volves simplified relation to deaerator and no recirculation.

Brine concentration in hot stage F E, MEF Feed to het stage should be ofas low a concentration as possible. In this system it is unevaporatedsea water. No brine recirculation. Consequently les's scale formation. i

Brine discharge concentration F E, MEF Maximum limited only by possiblescale on 1o temperature stage. Vapor piping E F, MEF External vaporpiping is undesirable and is not y used in MEF system except for steamfeed. Heat transfer coenicients E F MEF Oerllcoecients will be above1,000 B.t.u./hr. Utilization of pressure drop between stages to F E, MEFFlow through brine tubes is caused by this and improve heat transfer.gravity. No advantage is taken of this in the A multi-stage flashsystem. Number of pumps E F MEF The fewer the better. Pumping powerrequired F, E MEF No recirculation, interstage pumpingor pumping toexchangers.

External heat exchangers E F, MEF None required.

Allowable steam temperature F, E MEF The high desirable temperature ispossible because of lower brine concentration than F in hot stage andnnproved distribution over E in brine evaporation tubes.

Piping, liquid E F, MEF This external piping is kept to a minimum.

Feed pretreatment E, MEF F A finer screening or settling of the feed isrequired because the particle size must be smaller to pass through thissystem than in ash system. Otherwise treatment is about the same.

Feed heating E F, MEF Preheating of liquor in evaporator. Same asmultistage flash system. Evaporation in contact with metal surface withE MEF This is somewhat desirable from a thermodynamic condensation onother side. point of view but undesirable from heat transferconsiderations. This is not used in the multistage' ash system. Intimatecontact between liquid and vapor during v flashing assured by turbulenttwo phase dow Flash evaporation eiiciency F E, MEF through brine tubes.This does involve some Product salinity ontrainment of brine intoproduct (but less than 00 p.p.m.). Product is sterilized by hightemperure.

The MEF system should be located on a slope or Orientation of stages E,MEF be verticle. It could be operated on a horizontal Land area requiredF E MEF surface if brine pumps were added between stages as in themultiple eiect system. Estimated cost of product water from large plantE F MEF The oost should be below that for water from av largemulti-stage flash plant which has been estimated to be about $.50/1,000gallons! U.S. Department o Interior, Oice of Saline Water R & D ReportNo. 72, March 1963.

While the forms of embodiment herein shown and described, constitutepreferred forms, it is to be understood that other forms may be adoptedfalling within the scope of the claims that follow.

We claim:

1.. Those steps in a method of distilling liquid, which steps comprise:

(A) conducting liquid to a container in a closed tank;

(B) conducting the liquid from the container to a second container inthe tank through a plurality of tubes in the tank;

(C) heating the liquid in the tubes;

(D) causing a pressure drop and consequent vaporization of a portion ofthe liquid in the tubes by restricting the flow of liquid at the inletsof the tubes;

(E) condensing the vapor in the second container by causing the liquidwhich was conducted thereto, through a plurality of tubes in the secondcontainer and causing a pressure drop and consequent vaporization of aportion of the liquid in the second mentioncd tubes by restricting theiiow of liquid at the inlets of the second mentioned tubes, andimpinging the vapor, emanating from the rst mentioned tubes, ontheexterior of the second mentioned tubes;

(F) conducting the liquid and vapor from the outlets of the secondmentioned tubes to a third container in the tank;

(G) collecting and removing the condensate from the second containerthrough an outlet which is independent of the outlets of the secondmentioned tubes.

2. Those steps in the method as defined in claim 1,

characterized in that the liquid ilows at least partly by gravity fromthe rst mentioned container to the second mentioned container.

3. Those steps in the method as defined in claim 1,

characterized to include the step of:

(E) conducting the liquid to the rst mentioned con taincr in intimateheat exchange relation with at least one of the other containers.

4. A multiple effect ash evaporator, comprising in combination:

(A) a tank;

' (B) a second container in the tank including:

(l) a series of tubes extending therethrough and connected with thcfirst mentioned container; (2) flow restrictor means at the inlet endsof the tubes; (3) means for heating the liquid in the second containers;

(D) a third container connected with the outlet of said tubes and havinga vapor area and including:

(l) a liquid receiver for receiving liquid from the tubes of the secondmentioned container;

(2) a series of tubes connected with the receiver below the liquid levelin the latter;

(3) flow restrictor means at the inlet ends of the second mentionedtubes;

thc vapor emanating from said tubes of the second mentioned containerbeing directly impinged by the exterior of the tubes in the thirdmentioned container for causing condensation of the vapor;

(4) a receiver, independent of the liquid receiver and the secondmentioned series of tubes, for receiving the vapor which is condensed inthe third mentioned container, said condensate receiver having an outletindependent of the outlets in the second mentioned tubes.

5. A multiple effect flash evaporator as defined in claim 4,characterized in that the receiver of the third mentioned container isdisposed to receive liquid from the tubes of the second mentionedcontainer at least partly by gravity.

6. A multiple eect flash evaporator as defined in claim 4, characterizedin that the receiver of the third mentioned container is disposed belowthe tubes of the second mentioned container.

7. A multiple effect flash evaporator as defined in claim 4,characterized to include:

(E) means in intimate heat exchange relation with the third mentionedcontainer for delivering liquid to the first mentioned container.

8. A multiple effect flash evaporator as defined in claim 4Jcharacterized in that the receiver (C)(1) includes:

(a) a well extending below the first mentioned restrictor means.

9. A multiple effect flash evaporator as defined in claim 8,characterized in that means (D) for conducting the condensate from thethird mentioned container is in intimate heat exchange relation with theWell.

References Cited UNITED STATES PATENTS 378,843 2/1888 Lillie. 1,863,0767/1932 Hughes et al 202--174 2,334,959 11/ 1943 Rosenblad. 2,750,9996/1956 DeVries 159-18 3,021,265 2/ 1962 Sadtler et al. 159-20 3,303,1062/1967 Standiford 159-18 X 3,304,242 2/1967 Lockman 159-18 X FOREIGNPATENTS 74,691 12/1960 France. 576,838 8/1924 France. 281,743 3/ 1952Switzerland.

NORMAN YUDKOFF, Primary Examiner I. SOFER, Assistant Examiner U.S. Cl.X.R.

ggg UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 3,487, 873 Dated January 6, 1970 InVent0r(S) LeRov A. Bromlev. Stanlev M.Read & Anthonv J Diamond It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 5, line 58 cancel "38'l and substitute "238". Column 6, line 41cancel "assetsand substitute --assists;

line 64 cancel "259" and substitute --250.

Cancel Claim 4, and substitute the following claim:

4. A multiple effect flash evaporator, comprising in combination: (A) atank; (B) a container for liquid in the tank; (C) a second container inthe tank including:

(1) a series of tubes extending therethrough and connected with thefirst mentioned container;

(2) flow restrictor means at the inlet ends of the tubes;

(3) means for heating the liquid in the second container;

(D) a third container connected with the outlet of said tubes and havinga vapor area and including:

(1) a liquid receiver for receiving liquid from the tubes oi' the secondmentioned container;

(2) a series of tubes connected with the receiver below the liquid levelin the latter;

(3) flow restrictor means at the inlet ends of the second mentionedtubes;

the vapor emanating from said tubes of the second mentioned containerbeing directly impinged by the exterior of the tubes in the thirdmentioned container for causing condensation of the vapor;

(4) a receiver, independent of the liquid receiver and the secondmentioned series of tubes, for receiving the vapor which is condensed inthe third mentioned container, said condensate receiver having an outletindependent of the outlets in the second mentioned tubes.

SIGNED AND SEALED JuL 2 1 *l SEAL) Attest:

WILLIAM E. soHuYLER. JR-

Edward M. Fletcher, Jr. @omissioner of Patents Attesu'ng Officer

